<!DOCTYPE html>
<html>

<head>
<title>前端学习</title>
<meta charset="utf-8">
<meta http-equiv="cache-control" content="no-cache">
<link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
<script src="https://cdn.bootcss.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
<script src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.9.0.js"></script>
<style type="text/css">
    .but{
      float:right;
      margin-top: -70px;
    }
</style>
</head>

<body>
<div  class="container" >
<div class="row" >
  <div class="col-sm-6 col-md-4  col-xs-6" >
    <div class="thumbnail">
      <img src="../images/aa.jpg" alt="">
      <div class="caption">
        <h3>Thumbnail label</h3>
        <p>...</p>
        <p class="but"><a href="#" class="btn btn-default" role="button">开始游戏</a></p>
      </div>
    </div>
  </div>
  <div class="col-sm-6 col-md-4 col-xs-6" >
    <div class="thumbnail"  >
      <img src="../images/aa.jpg" alt="" >
      <div class="caption">
        <h3>Thumbnail label</h3>
        <p>...</p>
        <p class="but"><a href="#" class="btn btn-default" role="button">开始游戏</a></p>
      </div>
    </div>
  </div>
  <div class="col-sm-6 col-md-4 col-xs-6">
    <div class="thumbnail">
      <img src="../images/aa.jpg" alt="" >
      <div class="caption">
        <h3>Thumbnail label</h3>
        <p>...</p>
        <p class="but"><a href="#" class="btn btn-default" role="button">开始游戏</a></p>
      </div>
    </div>
  </div>
</div>
</div>
</body>

</html>